Mowing a lawn is necessary, but waiting for perfectly dry conditions is often unrealistic due to rain or heavy morning dew. While waiting for the grass to dry completely remains the ideal approach, scheduling sometimes requires proceeding with caution. Cutting wet grass can be done successfully, but only by implementing specific techniques to protect your turf and equipment from damage. Understanding the risks and preparing appropriately will ensure a clean cut.
The Risks of Mowing Wet Grass
Mowing saturated grass creates a high risk of damage to both the lawn and the mower. The water’s weight causes grass blades to bend over, resulting in an uneven cut where the mower tears the grass rather than slicing it cleanly. This tearing leaves ragged tips on the blades, which quickly turn brown and make the lawn vulnerable to fungal diseases like brown patch and leaf spot.
The soft, waterlogged soil is highly susceptible to compaction and rutting from the mower’s wheels. Driving over saturated ground creates deep, uneven grooves that restrict the grass roots’ ability to absorb water and nutrients. Furthermore, the high moisture content of the clippings causes them to clump together beneath the deck, reducing airflow and forcing the engine to work harder.
This sticky buildup causes rapid clogging, which strains the engine and can lead to overheating or bogging down. If left uncleaned, these wet clippings cling to the underside of the deck, trapping moisture against the metal and accelerating rust and corrosion. Operating any mower on wet, slippery grass also creates a safety hazard, increasing the risk of the operator slipping or losing traction. Corded electric models introduce the danger of electric shock.
Essential Equipment Preparation
Ensuring the mower blade is razor-sharp minimizes stress on the wet grass plant. A dull blade rips and bruises the blades, creating a large wound that heals slowly and invites turf disease. A freshly sharpened blade creates a clean incision, allowing the grass to recover quickly. This is especially important in moisture-rich conditions that favor pathogen growth.
The cutting deck must be raised significantly higher than the normal setting, often by at least one full notch or half an inch. This increase in height reduces the volume of wet grass entering the deck and minimizes resistance, helping to prevent the engine from bogging down. Raising the deck also helps avoid scalping the turf, which is a common issue when grass is weighed down and lying flat.
When dealing with wet grass, choose the discharge method that best handles the sticky, heavy clippings. Side discharge is the preferred option because it forcefully expels the clippings away from the deck, preventing the quick clogging that occurs with bagging. Mulching is strongly discouraged, as the wet material overwhelms the mulching chamber, leading to immediate gumming and deck buildup.
Optimized Mowing Technique
The most important adjustment is drastically reducing your ground speed during the cut. Moving slowly allows the blade time to lift and process the heavier, saturated grass without choking the engine or packing the deck. Maintaining the engine at full throttle is necessary to ensure the blade tip speed remains high enough to create the lift needed to cut the damp blades cleanly.
Only remove the top one-third of the grass blade length, or less if the grass is exceptionally wet or overgrown. Taking off too much at once will overload the mower, leading to excessive clumping and engine strain. If the grass is very tall, a two-stage process is recommended. First, cut the lawn at the highest setting, allow the clippings to dry slightly, and then make a second pass later at a lower height.
Use a wider than normal overlap on each pass, covering about half the width of the deck, to help scatter the heavy clippings more evenly. This wider path ensures the mower’s vacuum action distributes the material across a larger area. Varying your mowing pattern with each job, such as switching from straight rows to a spiral or zigzag, also helps to spread the weight of the mower and avoid creating permanent wheel ruts in the soft soil.
Necessary Post-Mowing Cleanup
Immediate and thorough cleaning of the equipment is mandatory after cutting wet grass to prevent long-term damage. The first safety measure is to turn off the engine, remove the ignition key, and disconnect the spark plug wire to ensure the machine cannot accidentally start. The mower should then be tipped onto its side, with the carburetor or air filter facing upward, to safely expose the underside of the deck.
The wet, caked-on grass must be scraped away immediately using a plastic putty knife or a long-handled scraper. This sticky material holds moisture against the metal, which rapidly promotes rust and corrosion, significantly shortening the deck’s lifespan. Once the deck is scraped clean, rinse the area with a garden hose or utilize the deck wash port. Ensure the engine is off before applying water.
The clumps of wet clippings that were discharged onto the lawn must be addressed promptly, as leaving them can smother and kill the grass underneath. Use a leaf blower or a lightweight fan rake to break apart and evenly spread the concentrated piles across the lawn surface. Allow the entire mower, including the deck, to air dry completely before storing it. Consider applying a coat of silicone lubricant spray to the clean, dry underside to help prevent future grass buildup.